Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

Copolymers and compositions thereof useful for forming self-imageable
films encompassing such copolymers are disclosed. Such copolymers
encompass norbornene-type repeating units and maleic anhydride-type
repeating units where at least some of such and maleic anhydride-type
repeating units have been ring-opened. The films formed from such
copolymer compositions provide self imageable, low-k, thermally stable
layers for use in microelectronic and optoelectronic devices.

Claims:

1. A layer forming polymer composition, comprising: a self-imageable
polymer consisting of norbornene-type repeating units and maleic
anhydride-type repeating units, where; such norbornene-type repeating
units are represented by Formula In, which are derived from
norbornene-type monomers represented by Formula I: ##STR00015## where m
is 0, 1 or 2, each R1, R2, R3 and R4 for the said
first type of repeating unit is independently a hydrogen or a hydrocarbyl
pendent group having high transparency in the visible light spectrum;
such maleic anhydride-type of repeating units are represented by one or
more of Formulae IIa, IIb and IIc, which are derived from maleic
anhydride monomers represented by Formula II: ##STR00016## where
R5 and R6 are each independently one of hydrogen, methyl,
ethyl, a fluorinated or perfluorinated methyl or ethyl, a linear or
branched C3-C9 hydrocarbyl group; a linear or branched
fluorinated or perfluorinated C3-C9 hydrocarbyl group; a
C6-C18 substituted or unsubstituted cyclic or polycyclic
hydrocarbyl group; a photo active compound (PAC); an epoxy resin
comprising at least two epoxy groups; and a solvent.

2. The layer forming polymer composition of claim 1, further comprising
maleic anhydride-type repeating units derived from maleic anhydride-type
monomers represented by Formula III: ##STR00017## where R7 and
R8 are the same or different and are selected from hydrogen, methyl
and ethyl.

3. The polymer composition of claim 1, where R5 is one of methyl,
ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert-butyl.

4. The polymer composition of claim 1, where the epoxy resin comprises
three epoxy groups;

5. The polymer composition of claims 2 or 2, where the PAC is Tris-P
3M6C-2-201, 4NT-300 or TS-300.

7. The polymer composition of claim 5, where R1-R4 are each
hydrogen, R5 is butyl and the epoxy resin is Techmore VG3101L
trimethylolpropane triglycidylether (TMPTGE) or bisphenol A epoxy resin
(LX-1).

8. The polymer composition of claim 6, where the PAC is Tris-P
3M6C-2-201, the epoxy resin is Techmore VG3101L and the solvent is
propylene glycol monomethyl ether acetate (PGMEA).

9. A. polymer layer formed from the polymer composition Of claim 1 having
a dielectric constant of 3.2 or at 1 MHz.

10. The polymer layer of claim 1 having a transparency at 400 nm of more
than 85% after curing at 250.degree.C. for 30 minutes.

Description:

CROSS-REFERENCE TO RELATED PATENT APPLICATION

[0001] The present patent application is entitled to and claims the
benefit of priority, under 35 U.S.C. §119 of U.S. Provisional Patent
Application Ser. No. 61/507685 filed Jul. 14, 2011, and U.S. Provisional
Patent Application Ser. No. 61/548832 filed Oct. 19, 2011, both of which
are incorporated herein by reference in their entirety.

TECHNICAL FIELD

[0002] The present invention relates generally to copolymers and
compositions thereof that encompass both norbornene-type repeating units
and non-norbornene-type repeating units that are useful for forming
self-imageable layers, and more specifically to such copolymers and
compositions thereof that encompass both repeating units derived from
norbornene-type monomers with repeating units derived from maleic
anhydride-type monomers for providing self-imageability to layers made
therefrom when such layers are image-wise exposed to actinic radiation.

BACKGROUND

[0003] The microelectronic, such as semiconductor and optoelectronic,
industries have seen the requirement for smaller and smaller device
geometries over the past several years. While in some areas of device
fabrication sub-micron device geometries have been common place for a
number of years, in other areas, such as liquid crystal displays (LCDs),
organic light emitting diodes (OLEDs) and a variety of radio frequency
(RI) and microwave devices (e.g. RFICs/MMICs, switches, couplers, phase
shifters, SAW filters and SAW duplexers), such device geometries are only
recently approaching sub 10 micron levels.

[0004] With such smaller geometries comes a requirement for dielectric
materials with low dielectric constants to reduce or eliminate any
cross-talk between adjacent signal lines or between a signal line and a
device feature (e.g. a pixel electrode) due to capacitive coupling,
Although many low dielectric (low-K) materials are available for
microelectronic devices, for optoelectronic devices such materials must
also be broadly transparent in the visible light spectrum, not require
high temperature processing (greater than 300° C.) that would be
incompatible with other elements of such an optoelectronic device, and be
both low-cost and feasible for large scale optoelectronic device
fabrication.

[0005] Thus, it would be desirable to have a material capable of forming a
self-imageable layer to avoid the used for depositing a separate imaging
layer. Such material should also be easy to apply to a substrate, have a
low dielectric constant (3.9 or less) and thermal stability to
temperatures in excess of 250° C.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Embodiments in accordance with the present invention are described
below with reference to the following accompanying figures and/or images.
Where drawings are provided, it will be drawings which are simplified
portions of a device provided for illustrative purposes only.

[0007] FIG. 1 is a flow diagram that depicts a method of making a (DRM)
ROMA copolymer embodiment in accordance with the present invention'

[0008] FIGS. 2a, 2b, 2c and 2d are portions of Infrared spectra that show
before and after carbonyl stretching frequencies for copolymers subjected
to dissolution rate modification process embodiments in accordance with
the present invention;

[0009] FIG. 3 is a graphical representation in the change in dissolution
rate versus reaction time for a ROMA copolymer subjected to dissolution
rate modification process embodiments in accordance with the present
invention;

[0010] FIGS. 4a and 4b are photomicrographs of 10 um and 5 um lines and
spaces obtained after an image-wise exposure of a film formed from a
(DRM) ROMA copolymer film embodiment in accordance with the present
invention.

DETAILED DESCRIPTION

[0011] Embodiments in accordance with the present invention are directed
to copolymers that encompass at least one repeating unit derived from a
norbornene-type monomer and at least one repeating unit derived from a
maleic anhydride-type monomer, as such are defined hereinafter, and to
compositions encompassing such copolymers, Such copolymer compositions
being capable of forming self-imageable films useful as layers in the
manufacture of microelectronic and optoelectronic devices. That is to say
that, after image-wise exposure to actinic radiation, such layers (or
films) can be developed to form patterned layers (or films), where such
pattern is reflective of the image through which the layers (or films)
was exposed. In this manner, structures can be provided that are, or are
to become, a part of such microelectronic and/or optoelectronic devices.

[0012] As used herein, the articles "a," "an," and "the" include plural
referents unless otherwise expressly and unequivocally limited to one
referent.

[0013] Since all numbers, values and/or expressions referring to
quantities of ingredients, reaction conditions, etc., used herein and in
the claims appended hereto, are subject to the various uncertainties of
measurement encountered in obtaining such values, unless otherwise
indicated, all are to be understood as modified in all instances by the
term "about."

[0014] Where a numerical range is disclosed herein such range is
continuous, inclusive of both the minimum and maximum values of the range
as well as every value between such minimum and maximum values. Still
further, where a range refers to integers, every integer between the
minimum and maximum values of such range is included. In addition, where
multiple ranges are provided to describe a feature or characteristic,
such ranges can be combined. That is to say that, unless otherwise
indicated, all ranges disclosed herein are to be understood to encompass
any and all sub-ranges subsumed therein. For example, a stated range of
from "1 to 10" should be considered to include any and all sub-ranges
between the minimum value of 1 and the maximum value of 10. Exemplary
sub-ranges of the range 1 to 10 include, but are not limited to, 1 to
6.1, 3.5 to 7.8, and 5.5 to 10.

[0015] As used herein, the terms "copolymer composition" or "polymer
composition" are used herein interchangeably and are meant to include at
least one synthesized polymer or copolymer, as well as residues from
initiators, solvents or other elements attendant to the synthesis of such
copolymers, where such residues are understood as not being covalently
incorporated thereto. Such residues and other elements considered as part
of the polymer composition are typically mixed or co-mingled with the
polymer such that they tend to remain therewith when it is transferred
between vessels or between solvent or dispersion media. A copolymer
composition can also include materials added after synthesis of the
copolymer to provide or modify specific properties of such composition.

[0016] As used herein, "hydrocarbyl" refers to a radical of a group that
contains carbon and hydrogen atoms, non-limiting examples being alkyl,
cycloalkyl, aryl, aralkyl, alkaryl, and alkenyl. The term
"halohydrocarbyl" refers to a hydrocarbyl group where at least one
hydrogen has been replaced by a halogen. The term perhalcarbyl refers to
a hydrocarbyl group where all hydrogens have been replaced by a halogen.

[0017] As used herein, "alkyl" refers to a methyl or ethyl group and a
linear or branched acyclic or cyclic, saturated hydrocarbon group having
a carbon chain length of, for example, from appropriate C3 to
C25 groups. Non-limiting examples of suitable alkyl groups include,
but are not limited to, --CH2)3CH3,
--(CH2)4CH3, --(CH2)5CH3,
--(CH2)9CH3, --(CH2)23CH3, cyclopentyl, and
cyclohexyl.

[0018] As used herein the term "aryl" refers to aromatic groups that
include, without limitation, groups such as phenyl, biphenyl, benzyl,
xylyl, naphthalenyl, anthracenyl and the like.

[0019] The terms "alkaryl" or "aralkyl" are used herein interchangeably
and refer to a linear or branched acyclic alkyl group substituted with at
least one aryl group, for example, phenyl, and having an alkyl carbon
chain length of appropriate C1 to C25. It will further be
understood that the above acyclic alkyl group can be a haloalkyl or
perhaloalkyl group.

[0020] As used herein the term "alkenyl" refers to ethylene or a linear or
branched acyclic or cyclic hydrocarbon group having at least one double
bond and having an alkenyl carbon chain length of appropriate C3 to
C25. Non-limiting examples include, among others, vinyl groups,
propenyl, butenyl and the alike.

[0021] As used herein the term "heterohydrocarbyl" refers to any of the
previously described hydrocarbyls, halohydrocarbyls and
perhalohydrocarbyls where at least one carbon of the carbon chain is
replaced with N, O, S, Si or P. Non-limiting examples include
heterocyclic aromatic groups such as pyrrolyl, furanyl, and the like, as
well as non-aromatic groups such as ethers, thioethers and silyl ethers.
The term "alkylol" refers to alkyl groups that include at least one
hydroxyl group.

[0022] It will additionally be understood that any of the hydrocarbyl,
halohydrocarbyl, perhalohydrocarbyl and heterohydrocarhyl moieties
described above can be further substituted, if desired. Non-limiting
examples of suitable substituent groups include, among others, hydroxyl
groups, benzyl groups, carboxylic acid and carboxylic acid ester groups,
amides and imides.

[0023] Embodiments in accordance with the present invention encompass
copolymers having at least one repeating unit derived from a
norbornene-type monomer as defined herein below and at least one
repeating unit derived from a maleic anhydride-type monomer as defined
herein below.

[0024] The terms "norbornene-type", "polycycloolefin" and "poly(cyclic)
olefin" are used interchangeably herein and refer to monomers (or the
resulting repealing unit), that encompass at least one norbornene moiety
such as the moiety shown below:

##STR00001##

[0025] Such moiety is the simplest norbornene-type or poly(cyclic) olefin
monomer, bicyclo[2.2.1]hept-2-ene, commonly referred to as norbornene. As
described above, the term "norbornene-type" monomer or repeating unit is
used herein to encompass norbornene itself as well as any substituted
norbornene(s), and any substituted and unsubstituted higher cyclic
derivatives thereof. Formulae I and Ia, shown below, are representative
of norbornene-type monomers and norbornene-type repeating units
encompassed by embodiments in accordance with the present invention,
respectively:

##STR00002## [0026] where m is an integer ranging from 0 to 5 and
each occurrence of R1, R2, R3 and R4 independently
represents hydrogen or a hydrocarbyl.

[0027] As used herein, the term "maleic anhydride-type" will be understood
to refer to monomers that encompass at least one maleic anhydride-type
moiety such shown below by Formula II and to repeating units derived
therefrom, such as shown below by Formulae IIa, IIb and IIc:

##STR00003## [0028] where R5 and R6 are the same or
different hydrocarbyl.

[0029] It will also be understood that the term "maleic anhydride-type
monomer" is inclusive of monomers in accordance with Formula III

##STR00004## [0030] where R7 and R8 are the same or
different and are selected from hydrogen, methyl and ethyl. Further it
will understood that just as the repeat units of Formulae III, IIb and
IIc can be derived from the monomer of Formula analogous repeat units can
be derived from the maleic anhydride-type monomer of Formula III and are
encompassed by embodiments in accordance with the present invention.

[0031] Useful monomers for embodiments in accordance with the present
invention are described generally herein and are further described by the
monomer and substituent structures provided herein. With regard to the
polymer composition embodiments of the present invention, it will be
noted that such compositions can encompass a single copolymer
encompassing at least one norbornene-type repeating unit and at least one
maleic anhydride-type repeating unit. In other embodiments, such polymer
compositions can encompass a single copolymer encompassing two or more
distinct types of norbornene-type repeating units and at least one maleic
anhydride-type repeating unit, or a single copolymer encompassing at
least one norbornene-type repeating unit and two or more distinct types
of maleic anhydride-type of repeating units.

[0032] In still other embodiments, the polymer compositions can encompass
a blend of polymers encompassing at least two polymers such as described
above or one or more of such a copolymer and a norbornene-type
homopolymer.

[0033] When any of R1, R2, R3, R4.sub., R5 and
R6 is a hydrocarbyl group, such group can alternately be described
as being any C1 to C30 alkyl, aryl, aralkyl, alkaryl,
cycloalkyl, or heteroalkyl group. Representative alkyl groups include,
but are not limited to, methyl, ethyl, propyl, isopropyl, butyl,
isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, heptyl, octyl, nonyl,
and decyl. Representative cycloalkyl groups include, but are not limited
to, adamantyl, cyclopentyl, cyclohexyl, and cyclooctyl. Representative
aryl groups include, but are not limited to, phenyl, naphthyl, and
anthracenyl. Representative aralkyl groups include, but are not limited
to, benzyl and phenethyl. In addition, it should be noted that the
hydrocarbyl groups mentioned above can be substituted, that is to say at
least one of the hydrogen atoms can be replaced with, for example,
C1-C10 alkyl, haloalkyl, perhaloalkyl, aryl, and/or cycloalkyl
group(s). Representative substituted cycloalkyl groups include, among
others, 4-t-butylcyclohexyl and 2-methyl-2-adamantyl. A non-limiting
representative substituted aryl group is 4-t-butylphenyl.

[0034] Further, any one or more of R1 to R6 can also be a
halohydrocarbyl group, where such group includes any of the hydrocarbyls
mentioned above where at least one, but less than all, of the hydrogen
atoms of the hydrocarbyl is replaced by a halogen (fluorine, chlorine,
bromine or iodine). Additionally, any one or more of R1 to R6
can be a perhalocarbyl group, where such group includes any of the
hydrocarbyls mentioned above where all of the hydrogen atoms of the
hydrocarbyl are replaced by a halogen. Representative perfluorinated
substituents include, but are not limited to, perfluorophenyl,
perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, and
perfluorohexyl.

[0035] In some embodiments the perhalohydrocarbyl groups can include
perhalogenated phenyl and perhalogenated alkyl groups. In other
embodiments, the perfluorinated groups can include perfluorophenyl,
perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, and
perfluorohexyl. In addition to halogen substituents, cycloalkyl, aryl and
aralkyl groups of such embodiments can be substituted with any
C1-C5 alkyl, C1-C12 haloalkyl, aryl, and/or
cycloalkyl group.

[0036] As mentioned above, embodiments in accordance with the present
invention are directed to copolymers encompassing both norbornene-type
repeating units and maleic-anhydride type repeating units and
compositions made therefrom. Such copolymer compositions being capable of
forming films useful as self-imageable layers in the manufacture of
microelectronic and optoelectronic devices. That is to say that when
image-wise exposed to actinic radiation, such layers (or films) can be
developed to form a patterned film, where such pattern is reflective of
the image through which the film was exposed.

[0037] In this manner, structures can be provided that are, or are to
become, a part of such microelectronic and/or optoelectronic devices. For
example, such films may be useful as low-K dielectric layers in liquid
crystal displays or in microelectronic devices. It will be noted that
such examples are only a few of the many uses for such a self-imageable
film, and such examples do not serve to limit the scope of such films or
the polymers and polymer compositions that are used to form them.

[0038] Thus embodiments in accordance with the present invention encompass
copolymers encompassing repeating units derived from the monomers
described hereinabove and which are obtainable via free radical
polymerization reaction using methods known to those skilled in the art
to form a copolymer intermediate encompassing at least one type of
norbornene-type repeating unit and maleic anhydride repeating units.
Non-limiting examples of initiators that may be used in the free radical
polymerization reaction include, for instance, azo compounds and organic
peroxides. Non-limiting examples of azo compounds include
azobisisobutyronitrile (AIBN), (E)-dimethyl
2,2'-(diazene-1,2-diyl)bis(2-methylpropanoate (AMMP),
(E)-2,2'-(diazene-1,2-diyl)bis(2,4-dimethylpentanenitrile (ADMPN) and
1,1'-azobis(cyclohexanecarbonitrile) (ABCN). Non-limiting examples of
organic peroxides include hydrogen peroxide, di-t(tertiary)-butyl
peroxide, benzoyl peroxide, and methyl ethyl ketone peroxide.

[0039] Some polymer embodiments in accordance with the present invention,
are formed from the aforementioned copolymer intermediate by contacting
such intermediate with reagent(s) sufficient to cause the maleic
anhydride repeating units to ring open and thus form repeating units in
accordance with Formulae IIa and/or IIb. Such a polymer embodiment being
represented by Formula IVa, where generally, norbornene-type repeating
units and maleic anhydride-type repeating units are found to be
alternating.

##STR00005##

[0040] Other copolymer embodiments in accordance with the present
invention, encompass at least one norbornene-type repeating unit in
accordance with Formula Ia, at least one ring-opened
maleic-anhydride-type repeating unit in accordance with Formulae IIa
and/or IIb, and a repeating unit in accordance with Formula IIc as shown
by Formula IVb. The norbornene-type repeating units and maleic
anhydride-type repeating units of a copolymer embodiment represented by
Formula IVb, again, are found to be alternating.

##STR00006##

[0041] where for Formulae IVa and IVb, R2, R3, R4, R5
and R6 are as previously defined and while not specifically shown,
it will be understood that Formulae IVa and IVb are inclusive of maleic
anhydride-type repeating units derived from the monomer represented by
Formula III.

[0042] Polymer composition embodiments in accordance with the present
invention generally encompass, in addition to a polymer embodiment, at
least one casting solvent, at least one Photo Active Compound (PAC) and
at least one epoxy resin, where such epoxy resin encompasses at least two
epoxy groups.

[0045] For TS-200, 67% of D is DNQ, For TS-250, 83% of D is DNQ, For
TS-300, 100% of D DNQ; and where `D` or `Q` refers to DNQ which is one of
the diazonaphthoquinone-type structures below, or a hydrogen atom.

##STR00008##

[0046] Exemplary PACs also include, but are not limited to, the PACs
disclosed in U.S. Pat. No. 7,524,594 beginning at column 13, line 39 and
continuing through Collective Formula 9z at column 20, Such PACs being
provided below.

[0048] Still other exemplary epoxy resins or cross-linking additives
include, among others Araldite MTO163 and Araldite CY179 (manufactured by
Ciba Geigy); and EHPE-3150, Epolite GT300 and (manufactured by Daicel
Chemical).

[0049] Some embodiments of the present invention encompass structures,
such as optoelectronic structures, which include at least one
self-imageable layer formed from a film of a copolymer composition
embodiment in accordance with the present invention. As previously
mentioned, the copolymer of such a composition embodiment encompasses at
least one repeating unit derived from a norbornene-type monomer and at
least repeating unit derived from a maleic anhydride-type monomer. The
polymer composition embodiment further encompassing at least one casting
solvent, at least one photo active compound (PAC) and at least one epoxy
resin.

[0050] With regard to the composition embodiments of the present
invention, such embodiments provide for "positive tone" self-imageable
films. Generally, for positive tone compositions, exposed portions of a
layer formed from such composition become more soluble in a developer
solution than portions unexposed to such radiation. In each case, the
more soluble portions are washed away during an image development process
using an aqueous base solution. The aforementioned exposed portions'
increased solubility in aqueous base being the result of the at least one
PAC added to the composition generating a carboxylic acid which enhances
the solubility of the exposed portion in an aqueous alkali solution as
compared to any unexposed portions where the PAC remains unchanged.

[0051] The aforementioned structure embodiments of the present invention
are readily formed by first casting a polymer composition over an
appropriate substrate to form a layer thereof, then heating the substrate
to an appropriate temperature for an appropriate time, where such time
and temperature are sufficient to remove essentially all of the casting
solvent of such composition. After such first heating, the layer is
image-wise exposed to an appropriate wavelength of actinic radiation. As
one of skill in the art knows, the aforementioned image-wise exposure
causes the PAC contained in exposed portions of the layer to undergo a
chemical reaction that enhances the dissolution rate of such exposed
portions to an aqueous base solution (generally a solution of tetramethyl
ammonium hydroxide (TMAH)). In this manner, such exposed portions are
removed and unexposed portions remain. Next a second heating is performed
to cause cross-linking of portions of the polymer with the epoxy
additive, thus essentially "curing" the polymer of such unexposed
portions to form an aforementioned structure embodiment of the present
invention.

[0052] The following examples, without being limiting in nature,
illustrate methods for making copolymer embodiments in accordance with
the present invention. Such examples illustrate first forming the
previously mentioned copolymer intermediate, referred to herein as a
cyclic olefin maleic anhydride (COMA) copolymer. Additionally, such
examples describe forming ring-opened analogs of such COMA copolymer
intermediates, referred to herein as ROMA copolymers, and further still,
such examples disclose forming dissolution rate modified (DRM) ROMA
copolymers.

[0053] Referring now to FIG. 1, a general process flow useful for forming
such (DRM) ROMA copolymers is provided. Specifically, Step 100 is the
polymerization of a norbornene-type monomer and maleic anhydride in an
appropriate polymerization solvent to form the aforementioned COMA
copolymer. In Step 110, the solution of such COMA copolymer first treated
with a mixture of a strong base to open the anhydride ring an alcohol,
for example methanol or butanol, to form a ROMA copolymer having
monoester and salt moieties. Such ROMA copolymer is then treated with an
acid such as formic acid or aqueous hydrochloric acid in Step 120 to
convert the carboxylic acid salt moiety to its acid form. In Step 130 the
ROMA copolymer of Step 120 is washed with an appropriate mixture of
aqueous and organic solvents to remove any remaining inorganics leaving
the copolymer and any aqueous insoluble residual monomers in an organic
phase. This is followed by Step 140 where another mixture of aqueous and
organic solvents is used to extract such residual monomers leaving a
solution of an essentially pure ROMA copolymer. In Step 150, the ROMA
copolymer of Step 140 is heated in the presence of an excess of an
alcohol to take advantage of the equilibrium shown below, thereby
reducing the concentration of carboxylic acid moiety of the ROMA
copolymer to reduce the copolymer's solubility, and hence its dissolution
rate (DR) in aqueous base, thus forming the aforementioned (DRM) ROMA
copolymer. In Step 160, the (DRM) ROMA copolymer is purified and
generally transferred by a solvent exchange process to an appropriate
casting solvent. In Step 170, additives such as an appropriate PAC and an
appropriate crosslinking compound are added to form a useable (DRM) ROMA
copolymer composition.

##STR00014##

[0054] In addition, such examples illustrate forming copolymer composition
embodiments in accordance with the present invention and discuss the
various evaluations performed on such copolymer, copolymer composition
and film embodiments of the present invention that serve to characterize
such embodiments.

[0055] With regard to characterization testing, molecular weights (Mw and
Mn) were determined by Gel Permeation Chromatography (GPC) using
polystyrene standards. Where Gas Chromatography was used

[0057] Maleic Anhydride (MA, 7.4 g, 75.0 mmol), 2-Norbornene (NB, 7.1 g,
75.0 mmol) and AIBN (1.2 g, 7.5 mmol) was dissolved in THF (20.4 g) and
charged to an appropriately sized reaction vessel. The solution was
sparged with nitrogen for 10 min to remove oxygen and then heated to
70° C. The mixture was allowed to stir at 70° C. for 5.0
hr, after which the solution was cooled to room temperature. The reaction
mixture was then diluted with 2.0 g of THF and was added to hexane (1 L)
to give a white powder that was filtered and dried in a vacuum oven at
80° C. for 16 hr. Approximately, 13.0 g (90%) of the MA/NB polymer
was isolated (GPC Mw=4,100 Mn=1,800).

Example A2

Polymer Synthesis of MA/BuNB

[0058] Maleic Anhydride (MA, 9.8 g, 100 mmol), 5-Butyl-2-norbornene (BuNB,
15.0 g, 100 mmol) and AIBN (1.64 g, 10.0 mmol) was dissolved in THF (37.2
g) and charged to an appropriately sized reaction vessel. The solution
was sparged with nitrogen for 10 min to remove oxygen and then heated to
70 ° C. The mixture was allowed to stir at 70° C. for 16
hr, after which the solution was cooled to room temperature. The reaction
mixture was added to hexane (2 L) to give a white powder that was
filtered and dried in a vacuum oven at 80° C. for 1 hr.
Approximately, 19.3 g (78%) of the MA/BuNB polymer was isolated (GPC
Mw=3,200 Mn=1,900).

Example A3

Polymer Synthesis of MA/NB/BuNB

[0059] Maleic Anhydride (MA, 7.4 g, 75.0 mmol), 2-Norbornene (NB, 3.5 g,
37.5 mmol), 5-Butyl-2-norbornene (BuNB, 5.6 g, 37.5 mmol) and AIBN (1.2
g, 7.5 mmol) was dissolved in THF (23.6 g) and charged to an
appropriately sized reaction vessel. The solution was sparged with
nitrogen for 10 min to remove oxygen and then heated to 70° C. The
mixture was allowed to stir at 70° C. for 20.5 hr, after which the
solution was cooled to room temperature. The reaction mixture was diluted
with 20 g of THF and added to hexane (1 L) to give a white powder that
was filtered and dried in a vacuum oven at 80° C. for 16 hr.
Approximately, 14.5 g (88%) of the MA/NB/BuNB polymer was isolated (GPC
Mw=3,500 Mn=1,700).

Example A4

Polymer Synthesis of MA/HxNB/NBC4F9

[0060] Maleic Anhydride (MA, 7.4 g, 75.0 mmol), 5-Hexyl-2-norbornene
(HxNB, 10.7 g, 60.0 mmol), 5-Perfluorobutyl-2-norbornene
(NBC4F9, 4.7 g, 15.0 mmol) and AIBN (1.23 g, 7.5 mmol) was
dissolved in THF (30.4 g) and charged to an appropriately sized reaction
vessel. The solution was sparged with nitrogen for 10 min to remove
oxygen and then heated to 70° C. The mixture was allowed to stir
at 70° C. for 20.5 hr, after which the solution was cooled to room
temperature. The reaction mixture was added to hexane (1 L) to give a
white powder that was filtered and dried in a vacuum oven at 80°
C. for 16 hr. Approximately, 14.3 g (66%) of the MA/HxNB/NBC4F9
polymer was isolated (GPC Mw=3,200 Mn=2,000).

Example A5

Polymer Synthesis of MA/PENB

[0061] Maleic Anhydride (MA, 7.4 g, 75.0 mmol), Phenyl Ethyl Norbornene
(PENB, 14.9 g, 75.0 mmol) and AIBN (1.2 g, 7.5 mmol) was dissolved in THF
(32.1 g) and charged to an appropriately sized reaction vessel. The
solution was sparged with nitrogen for 10 min to remove oxygen and then
heated to 70° C. The mixture was allowed to stir at 70° C.
for 17.5 hr, after which the solution was cooled to room temperature. The
reaction mixture was diluted with 30 g of THF and added to hexane (1 L)
to give a white powder that was filtered and dried in a vacuum oven at
80° C., for 16 hr. Approximately, 16.7 g (75%) of the MA/PENB
polymer was isolated (GPC Mw=3,400 Mn=1,500).

[0062] ROMA Copolymer Synthesis

[0063] Examples B1 through B5 illustrate a method of ring-opening the
maleic anhydride repeating units of the COMA copolymers of Examples A1
through A5 with BuOH, respectively. Examples B6 and B7 illustrate a
method of both forming a COMA copolymer of MA and PENB and ring-opening
the maleic anhydride repeating units that COMA copolymer with BuOH,
Examples B8 through B12 illustrate methods of ring-opening the COMA
copolymer of Example A1 with different alcohols. Examples B13 and B14
illustrate a method of both forming a COMA copolymer of MA and PENB and
ring-opening the maleic anhydride repeating units that COMA copolymer
with MeOH. Example B15 illustrates a method of first forming a COMA
copolymer, ring-opening that copolymer to form a ROMA copolymer and then
performing a dissolution rate modification of that ROMA copolymer.
Example 15 is consistent with the process depicted in FIG. 1.

Example B1

ROMA Copolymer of MA/NB with BuOH

[0064] An appropriately sized reaction vessel was loaded with NaOH (2.3 g,
57.3 mmol), BuOH (19.3 g, 260 mmol) and THF (20.0 g). The mixture was
allowed to stir for 1 hr at 70° C. and then the polymer obtained
in Example 1 (10.0 g) in 20 g of THF was added. After 3 hr of the
reaction at 70° C., the mixture was cooled to room temperature.
The reaction mixture was treated with cone. HClaq for protonation, and
then washed three times to remove residual salts and acid. The organic
phase was separated and then concentrated in vacuo, redissolved in THF to
form an approximately 20 wt % copolymer solution and then the copolymer
was precipitated by adding the THF solution to hexane (20 fold excess).
The copolymer was separated by filtration and dried in a vacuum oven at
80° C. for 16 hr. Approximately, 10.1 g (73%) of the ROMA polymer
of MA/NB with BuOH was isolated (GPC Mw=4,400 Mn=2,400).

Example B2

ROMA Copolymer of MA/BuNB with BuOH

[0065] An appropriately sized reaction vessel was loaded with NaOH (0.9 g,
22.3 mmol), BuOH (7.5 g, 100.6 mmol) and THF (15.0 g). The mixture was
allowed to stir for 1 hr at 70° C. and then the polymer obtained
in Example 2 (5.0 g) in 7.5 g of THF was added. After 3 hr of the
reaction at 70° C., the mixture was cooled to room temperature.
The reaction mixture was treated with cone. HClaq for protonation, and
then washed three times to remove residual salts and acid. The organic
phase was separated and then concentrated in vacuo, redissolved in THF to
form an approximately 20 wt % copolymer solution and then the copolymer
was precipitated by adding the THF solution to hexane (20 fold excess).
The copolymer was separated by filtration and dried in a vacuum oven at
80° C. for 16 hr. Approximately, 4.7 g (72%) of the Ring-opening
polymer of MA/BuNB with BuOH was isolated (GPC Mw=3,800 Mn=2,300).

Example B3

ROMA Copolymer of MA/NB/BuNB with BuOH

[0066] An appropriately sized reaction vessel was loaded with NaOH (2.00
g, 50.0 mmol), BuOH (16.82 g, 227 mmol) and THF (15.0 g). The mixture was
allowed to stir for 1 hr at 70° C. and then the polymer obtained
in Example 3 (10.0 g) in 15.0 g of THF was added. After 3 hr of the
reaction at 70 ° C., the mixture was cooled to room temperature.
The reaction mixture was treated with conc. HClaq for protonation, and
then washed three times to remove residual salts and acid. The organic
phase was separated and then concentrated in vacuo, redissolved in THF to
form an approximately 20 wt % copolymer solution and then the copolymer
was precipitated by adding the THF solution to hexane (20 fold excess).
The copolymer was separated by filtration and dried in a vacuum oven at
80° C. for 16 hr. Approximately, 10.2 g (76%) of the Ring-opening
polymer of MA/NB/BuNB with BuOH was isolated (GPC Mw3,800 Mn=2,200).

Example B4

ROMA Copolymer of MA/HxNB/NBC4F9 with BuOH

[0067] An appropriately sized reaction vessel was loaded with NaOH (1.45
g, 36.3 mmol), BuOH (12.22 g, 165 mmol) and THF (20.0 g). The mixture was
allowed to stir for 1 hr at 70° C. and then the polymer obtained
in Example 4 (10.00 g) in 15.0 g of THF was added. After 3 hr of the
reaction at 70° C., the mixture was cooled to room temperature.
The reaction mixture was treated with cone. HClaq for protonation, and
then washed three times to remove residual salts and acid. The organic
phase was separated and then concentrated in vacuo, redissolved in THF to
form an approximately 20 wt % copolymer solution and then the copolymer
was precipitated by adding the TIFF solution to hexane (20 fold excess).
The copolymer was separated by filtration and dried in a vacuum oven at
80° C. for 16 hr. Approximately, 7.2 g (58%) of the Ring-opening
polymer of MA/HxNB/NBC4F9 with BuOH was isolated (GPC Mw=3,700
Mn=2,400),

Example B5

ROMA Copolymer of MA/PENB with BuOH

[0068] An appropriately sized reaction vessel was loaded with NaOH (0.7 g,
18.5 mmol), BuOH (3.7 g, 50.7 mmol) and THF (20.0 g). The mixture was
allowed to stir for 1 hr at 70° C. and then the polymer obtained
in Example 5 (5.0 g) in 20.0 g of THF was added. After 3 hr of the
reaction at 70° C., the mixture was cooled to room temperature.
The reaction mixture was treated with cone. HClaq for protonation, and
then washed three times to remove residual salts and acid, The organic
phase was separated and then concentrated in vacuo, redissolved in THF to
form an approximately 20 wt % copolymer solution and then the copolymer
was precipitated by adding the THF solution to hexane (20 fold excess).
The copolymer was separated by filtration and dried in a vacuum oven at
80° C. for 16 hr. Approximately, 4.7 g (75%) of the ring-opening
polymer of MA/PENB with BuOH was isolated (GPC Mw=3,500 Mn=2,200).

Example B6

ROMA Copolymer of MA/PENB with BuOH

[0069] Maleic Anhydride (MA, 19.6 g, 200.0 mmol), Phenyl Ethyl Norbornene
(PENB, 39.6 g, 200 mmol) and AIBN (3.3 g, 20.0 mmol) was dissolved in THF
(36.2 g) and charged to an appropriately sized reaction vessel. The
solution was sparged with nitrogen for 10 min to remove oxygen and then
heated to 60° C. The mixture was allowed to stir at 60° C..
for 23 hr, after which the solution was diluted to 20 wt % with 181.3 g
of THF. The resulting solution was added to the suspension of NaOH (8.8
g, 220 mmol), BuOH (74.0 g, 1 mol) and THF (80.00 which were mixed at
70° C. for 1 hr. The mixture was allowed to stir for 2 hr at
70° C. and then was cooled to room temperature. The reaction
mixture was treated with cone. HClaq for protonation, and then washed
three times to remove residual salts and acid. The organic phase was
separated and then concentrated in vacuo, redissolved in THF to form an
approximately 20 wt % copolymer solution and then the copolymer was
precipitated by adding the THF solution to hexane (20 fold excess). The
copolymer was separated by filtration and dried in a vacuum oven at
80° C.. for 16 hr. Approximately, 44.4 g (75%) of the ROMA
copolymer of MA/PENB with BuOH was isolated (GPC Mw=7,700 Mn=4,000).

Example B7

ROMA Copolymer of MA/PENB with BuOH

[0070] Maleic Anhydride (MA, 19.6 g, 200.0 mmol), Phenyl Ethyl Norbornene
(PENB, 39.6 g, 200 mmol) and AIBN (3.3 g, 20.0 mmol) was dissolved in
EtOAc (36.2 g) and charged to an appropriately sized reaction vessel. The
solution was sparged with nitrogen for 10 min to remove oxygen and then
heated to 60° C. The mixture was allowed to stir at 60° C.,
for 20 hr. The reaction mixture was concentrated in vacuo and redissolved
in THF (20 wt %). The resulting solution was added to the suspension of
NaOH (8.80 g, 220 mmol), BuOH (74.12 g, 1 mol) and TI-IF (74.12 g) which
were mixed at 70° C. for 1 hr. The mixture was allowed to stir for
2 hr at 70° C. and then was cooled to room temperature. The
reaction mixture was treated with cone. HClacq for protonation, and then
washed three times to remove residual salts and acid. The organic phase
was separated and then concentrated in vacuo, redissolved in THF to form
an approximately 20 wt % copolymer solution and then the copolymer was
precipitated by adding the THF solution to hexane (20 fold excess). The
copolymer was separated by filtration and dried in a vacuum oven at
80° C. for 16 hr. Approximately, 37.5 g (51%) of the ROMA
copolymer of MA/PENB with BuOH was isolated (GPC Mw=9,900 Mn=5,400).

Example B8

ROMA Copolymer of MA/NB with tert-BuOH

[0071] An appropriately sized reaction vessel was loaded with NaOH (1.1 g,
28.5 mmol), t-BuOH (5.8 g, 77.8 mmol) and THF (20.0 g). The mixture was
allowed to stir for 3 hr at 70° C. and then the polymer obtained
with the same method in Example 1 (5.0 g) in 20.0 g of THF was added.
After 16 hr of the reaction at 70° C., the mixture was cooled to
room temperature. The reaction mixture was treated with cone. HClaq for
protonation, and then washed three times to remove residual salts and
acid. The organic phase was separated and then concentrated in vacuo,
redissolved in THF to form an approximately 20 wt % copolymer solution
and then the copolymer was precipitated by adding the THF solution to
hexane (20 fold excess). The copolymer was separated by filtration and
dried in a vacuum oven at 80° C. for 16 hr. Approximately, 4.5 g
(65%) of the ring-opening polymer of MA/NB with t-BuOH was isolated (GPC
Mw=3,000 Mn=1,500).

Example B9

ROMA Copolymer of MA/NB with 2-Methyl-2-Adamantanol

[0072] An appropriately sized reaction vessel was loaded with NaOH (1.1 g,
28.5 mmol), 2-Methyl-2-adamantanol (8.7 g, 52.0 mmol) and THF (40.0 g).
The mixture was allowed to stir for 3 hr at 70 ° C. and then the
polymer obtained in Example 1 (5.0 g) in 20.0 g of THF was added. After
16 hr of the reaction at 70° C., the mixture was cooled to room
temperature. The reaction mixture was treated with cone. HClaq for
protonation, and then washed three times to remove residual salts and
acid. The organic phase was separated and then concentrated in vacuo,
redissolved in THF to form an approximately 20 wt % copolymer solution
and then the copolymer was precipitated by adding the THF solution to
hexane (20 fold excess). The copolymer was separated by filtration and
dried in a vacuum oven at 80° C. for 16 hr. Approximately, 5.31 g
(57%) of the ring-opening polymer of MA/NB with 2-Methyl-2-adamantanol
was isolated (GPC Mw=3,000 Mn=1,500).

Example B10

ROMA Copolymer of MA/NB with 2,2,3,3,4,4,4-heptafloro-1-butanol

[0073] An appropriately sized reaction vessel was loaded with NaOH (1.1 g,
28.5 mmol), 2,2,3,3,4,4,4-heptafluoro-1-butanol (7.8 g, 39.0 mmol) and
THF (20.0 g). The mixture was allowed to stir for 3 hr at 70° C.
and then the polymer obtained in Example 1 (5.0 g) in 20.0 g of THF was
added. After 16 hr of the reaction at 70° C., the mixture was
cooled to room temperature. The reaction mixture was treated with conc.
HClaq for protonation, and then washed three times to remove residual
salts and acid. The organic phase was separated and then concentrated in
vacuo, redissolved in THF to form an approximately 20 wt % copolymer
solution and then the copolymer was precipitated by adding the THF
solution to hexane (20 fold excess). The copolymer was separated by
filtration and dried in a vacuum oven at 80° C. for 16 hr.
Approximately, 5.1 g (50%) of the ring-opening polymer of MA/NB with BuOH
was isolated (GPC Mw=3,600 Mn=1,900).

Example B11

ROMA Copolymer of MA/NB with 4-tert-Butylcyclohexanol

[0074] An appropriately sized reaction vessel was loaded with NaOH (1.1 g,
28.5 mmol), 4-tert-Butylcyclohexanol (12.2 g, 78.1 mmol) and THF (20.0
g). The mixture was allowed to stir for 3 hr at 70° C. and then
the polymer obtained in Example 1(5.0 g) in 20.0 g of THF was added,
After 16 hr of the reaction at 70° C., the mixture was cooled to
room temperature. The reaction mixture was treated with cone. HClaq for
protonation, and then washed three times to remove residual salts and
acid. The organic phase was separated and then concentrated in vacuo,
redissolved in THF to form an approximately 20 wt % copolytner solution
and then the copolymer was precipitated by adding the THF solution to
hexane (20 fold excess). The copolymer was separated by filtration and
dried in a vacuum oven at 80° C. for 16 hr. Approximately, 5.2 g
(58%) of the ring-opening polymer of MA/NB with 4-tert-Butylcyclohexanol
was isolated (GPC Mw=3,300 Mn=1,600).

Example B12

ROMA Copolymer of MA/NB with 4-tert-Butylphenol

[0075] An appropriately sized reaction vessel was loaded with NaOH (1.1 g,
28.5 mmol), 4-tert-Butylphenol (7.8 g, 52.0 mmol) and THF (15.0 g). The
mixture was allowed to stir for 3 hr at 70° C. and then the
polymer obtained in Example 1 (5.0 g) in 7.5 g of THF was added. After 16
hr of the reaction at 70° C., the mixture was cooled to room
temperature. The reaction mixture was treated with conc. HClaq for
protonation, and then washed three times to remove residual salts and
acid. The organic phase was separated and then concentrated in vacuo,
redissolved in THF to form an approximately 20 wt % copolymer solution
and then the copolymer was precipitated by adding the THF solution to
hexane (20 fold excess). The copolymer was separated by filtration and
dried in a vacuum oven at 80° C. for 16 hr. Approximately, 5.4 g
(61%) of the ring-opening polymer of MA/NB with 4-tert-Butylphenol was
isolated (GPC Mw=3,400 Mn=1,800).

Example B13

ROMA Copolymer of MA/PENB with MeOH

[0076] Maleic Anhydride (MA, 14.7 g, 150 mmol), Phenyl Ethyl Norbornene
(PENB, 29.7 g, 150 mmol) and AIBN (2.5 g, 15.0 mmol) was dissolved in THF
(27.1 g) and charged to a reaction vessel. The solution was sparged with
nitrogen for 10 min to remove oxygen and then heated to 60° C. The
mixture was allowed to stir at 60° C. for 24 hr, after which the
solution was diluted to 20 wt % with 148.04 g of THF. The resulting
solution was added to the suspension of NaOH (6.6 g, 165 mmol), MeOH
(24.0 g, 750 mmol) and THF (24.0 g) which were mixed at 70° C. for
1 hr. The mixture was allowed to stir for 3 hr at 70° C. and then
was cooled to room temperature. The reaction mixture was treated with
conc. HClaq for protonation, and then washed three times to remove
residual salts and acid. The organic phase was separated and then
concentrated in vacuo, redissolved in THE to form an approximately 20 wt
% copolymer solution and then the copolymer was precipitated by adding
the THE solution to hexane (20 fold excess). The copolymer was separated
by filtration and dried in a vacuum oven at 80° C. for 16 hr.
Approximately, 28.7 g (58%) of the Ring-opening polymer of MA/PENB with
MeOH was isolated (GPC Mw=6,400 Mn=3,500).

Example B14

ROMA Copolymer of MA/PENB with MeOH

[0077] Maleic Anhydride (MA, 14.7 g, 150 mmol), Phenyl Ethyl Norbornene
(PENB, 29.7 g, 150 mmol) and AIBN (2.5 g, 15.0 mmol) was dissolved in
EtOAc (27.1 g) and charged to a reaction vessel. The solution was sparged
with nitrogen for 10 min to remove oxygen and then heated to 60°
C. The mixture was allowed to stir at 60° C. for 24 hr. The
reaction mixture was concentrated in vacuo and redissolved in THF (20 wt
%). The resulting solution was added to the suspension of NaOH (6.6 g,
165 mmol), MeOH (24.0 g, 750 mmol) and THF (24.0 g) which were mixed at
70° C. for 1 hr. The mixture was allowed to stir for 3 hr at
70° C. and then was cooled to room temperature. The reaction
mixture was treated with conc. HClaq for protonation, and then washed
three times to remove residual salts and acid. The organic phase was
separated and then concentrated in vacuo, redissolved in THF to form an
approximately 20 wt % copolymer solution and then the copolymer was
precipitated by adding the THF solution to hexane (20 fold excess). The
copolymer was separated by filtration and dried in a vacuum oven at
80° C. for 16 hr. Approximately, 30.4 g (61%) of the Ring-opening
polymer of MA/PENB with MeOH was isolated (GPC Mw=9,700 Mn=5,300).

Example B15

(DRM) ROMA Copolymer of MA/NB with BuOH

[0078] Maleic Anhydride (MA, 98.1 g, 1.0 mol), 2-Norbornene (NB, 94.2 g,
1.0 mol) and AIBN (3.3 g, 20.0 mmol) were dissolved in THF (31.2 g) and
toluene (93.6 g) and charged to an appropriately sized reaction vessel,
The solution was sparged with nitrogen for 10 min to remove oxygen and
then heated to 60° C. with stirring. After 3 hr, THF (64.1 g) was
added and at 8 hr. AIBN (3.3 g, 20.0 mmol) and THF (39.4 g) were added
and the mixture was allowed to stir at 60° C. for additional 16
hr. Then the reaction mixture was diluted to 20 wt % with THF and the
resulting solution was added to a suspension of NaOH (44.1 g, 1.1 mol),
BuOH (370.9 g, 5.0 mol) and mixed at 65° C., for 3 hr. The mixture
was then cooled to 40° C., treated with cone. HClaq (126.2 g, 1.2
mol) for protonation, and then washed with toluene (384 g) and water (961
g) (1×), and THF (192 g) and water (961 g) (3×) to remove
inorganic residues. The organic phase was then separated and washed with
first a MeOH/water/hexane mixture (1×) and then a
MeOH/toluene/hexane mixture (2×) to extract any residual monomer.
After the extraction, BuOH (74.18 g, 1.0 mol) and PGMEA (611 g) was added
to the reaction mixture and evaporated until residual MeOH was less than
1%. Then the reaction mixture was heated up to 130° C. for
dissolution rate modification. Samples were taken to monitor the
dissolution rate of the copolymer. The reaction mixture was cooled and
solvent exchanged into PGMEA when the desired dissolution rate was
achieved, 651.4 g of the polymer as a 20 wt % solution was obtained (GPC
Mw =13,600 Mn=6,800).

[0079] While the above procedure includes a dissolution rate modification
step, it should be appreciated that such a processes can be accomplished
both in an alcohol-free and an alcohol-added environment. To that effect
a 20 wt % polymer solution of ROMA NB/MA-BuOH in PGMEA was heated at
125° C. for 3 hours. Infrared spectra, taken with a Nicolet
Avatar320 FT-IR spectrometer, of an initial sample and one taken after 3
hours of heating were obtained and portions thereof are provided in FIGS.
2a and 2b, respectively. In addition, another 20 wt % polymer solution of
a different ROMA NB/MA-BuOH in PGMEA was heated at 125° C. for 3
hours in the presence of BuOH. Infrared spectra, taken with a Nicolet
Avatar320 FT-IR spectrometer, of an initial sample and one taken after 3
hours of heating were obtained and portions thereof are provided in FIGS.
2c and 2d, respectively,

[0080] Turning first to FIGS. 2a and 2b, it can be seen that the two peaks
`A` that represent the carbonyl stretching frequencies of a MA ring
structure increase significantly between the spectra of the initial
sample (FIG. 2a) and the sample after 3 hours of heating (FIG. 2b), In
addition, Peak `B` which represents the carbonyl stretching frequency of
the butyl ester carbonyl and Shoulder `C` are seen to decrease in
intensity between the two spectra. Thus it is believed that these spectra
indicated that heating a copolymer with a BuOH ring-opened maleic
anhydride-type repeating unit in the absence of any added alcohol results
in some portion of those repeating units closing and that such ring
closure reduces the amount of carboxylic acid available to provide
solubility of the polymer in an aqueous base.

[0081] Referring now to FIGS. 2c and 2d, it can be seen that the two peaks
`A` that represent the carbonyl stretching frequencies of a MA ring
structure increase only slightly between the spectra of the initial
sample (FIG. 2c) and the sample after 3 hours of heating (FIG. 2d). In
addition, Peak `B` which represents the carbonyl stretching frequency of
the butyl ester carbonyl remains essentially constant while Shoulder `C`
is seen to decrease in intensity between the two spectra. Thus it is
believed that these spectra indicated that heating a copolymer with a
BuOH ring-opened maleic anhydride-type repeating unit in the presence of
added alcohol results in some portion of those repeating units closing
and other portions of those repeating units becoming the diester. Since
both ring closure and diester formation reduce the amount of carboxylic
acid available to provide solubility of the polymer in an aqueous base,
the dissolution rate of such initial copolymer is reduced.

[0082] Referring now to FIG. 3, it graphically represents a dissolution
rate modification step results in a lowering of the dissolution rate of
the original ROMA copolymer with or without the addition of an alcohol
moiety, for example benzyl alcohol. Thus it is believed that the results
shown in FIG. 3 further indicate that such a step must reduce the
availability of carboxylic moieties that had previously been present by
either or both of ring-closure or diesterification.

[0083] Alkali Dissolution Rate

[0084] The polymers from each of Examples B1-B12 and B15 were dissolved in
PGMEA to form a 25 wt % polymer solution. Each solution was spun onto a 3
inch silicon wafer and soft baked at 110° C. for 100 seconds to
give polymer films having a thickness of about 3 um, The wafers were
developed by immersing them in a 0.4% TMAH developer solution. A
dissolution rate of each film (shown below) was determined by measuring
the time to visually clear the polymer film.

[0086] The solutions of the polymer B1-B15 were applied onto glass wafers
as described above to give 3 um thick layer. Transparency at 400 nm was
measured before and after thermal treatment in air at 250° C./30
min. Pre-treatment, each of the films were at least 98% transparent,
while after the thermal treatment the polymers of Examples B2, B3 and B4,
all polymers with an alkylNB repeating unit, were significantly lowered.
B2 and B4 to 37% and 40%, respectively and B3 to 78%. With regard to the
others, only Examples B13 and B14 showed as much as a 10% lowering in %
transparency.

[0087] Tg

[0088] Tg of the polymers were measured by modulated DSC. The measurement
condition is 10° C./min under N2 flow. The copolymers of
Examples B1-B6, B11 and B12 each demonstrated a Tg of 150° C.
+/-10° C. while Examples B8-B10 demonstrated Tg of 183°C.,
186° C. and 177° C., respectively.

Copolymer Composition Examples

[0089] a: Dielectric Constant

[0090] The dielectric constant of a film prepared from a copolymer
composition of each of the copolymers of B1-B15 was measured at 1 KHz, 10
KHz, 100 KHz and 1 MHz following the technique of JIS-K6911, a Japanese
Industrial Standard. The methods of preparing each composition are
provided in Examples C1a-C15a. The film thickness of each film, needed to
calculate the dielectric constant, was measured by using Dainippon Screen
MFG CO., LTD. Lambda ace VM-1020.

Example C1a

[0091] The polymer from Example B1 was dissolved in PGMEA/EL (4/3, 16 wt
%) along with TrisP 3M6C-2-201 (25% on the polymer, from Toyo Gosei) and
with TMPTGE (20% on the polymer). The formulation was spun onto an
aluminum plate (200 um thickness, 100 mm ×100 mm) at 300 rpm for 23
sec, soft baked at 110° C. for 100 sec to give a polymer film of
about 3 microns, then exposed at 500 mJ/cm2 using a mask aligner having a
broad band Hg vapor light source (g, hand i bands). After exposure, the
wafer was post-exposure baked at 220° C., for 60 min under
nitrogen atmosphere to obtain a cured film.

Example C2a

[0092] The process of C1a was repeated except that the polymer from
Example B2 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with TMPTGE (20% on the polymer) and the
spinning condition was 300 rpm for 3 sec followed by 400 rpm for 20 sec.

Example C3a

[0093] The process of C1a was repeated except that the polymer from
Example B3 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with TMPTGE (20wt % on the polymer) and the
spinning condition was 300 rpm for 3 sec followed by 900 rpm for 20 sec.

Example C4a

[0094] The process of C1a was repeated except that the polymer from
Example B4 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with TMPTGE (20wt % on the polymer) and the
spinning condition was 300rpm for 3sec followed by 700 rpm for 20 sec.

Example C5a

[0095] The process of C1a was repeated except that the polymer from
Example B5 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with VG3101L (20 wt % on the polymer) and the
spinning condition was 300 rpm for 3 sec followed by 800 rpm for 20 sec.

Example C6a

[0096] The process of C1a was repeated except that the polymer from
Example B6 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with VG3101L (20wt % on the polymer) and the
spinning condition was 300 rpm for 3 sec and 1300 rpm for 20 sec.

Example C7a

[0097] The process of C1a was repeated except that the polymer from
Example B7 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with VG3101L, (20 wt % on the polymer) and the
spinning condition was 300 rpm for 3 sec followed by 1.370 rpm for 20
sec.

Example C8a

[0098] The process of C1a was repeated except that the polymer from
Example B8 was dissolved in PGMEA (25 wt %) along with TrisP PAC (25% on
the polymer) and with TMPTGE (20% on the polymer) and the spinning
condition was 300 rpm for 3 sec followed by 2000 rpm for 20 sec.

Example C9a

[0099] The process of C1a was repeated except that the polymer from
Example 39 was dissolved in PGMEA/MAK=3/1 (20 wt %) along with TrisP
3M6C-2-201 (25% on the polymer) and with TMPTGE (20% on the polymer) and
the spinning condition was 300 rpm for 3 sec followed by 1500 rpm for 20
sec.

Example C10a

[0100] The process of C1a was repeated except that the polymer from
Example B10 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with TMPTGE (20% on the polymer) and the
spinning condition was 300 rpm for 3 sec followed by 1000 rpm for 20 sec.

Example C11a

[0101] The process of C1a was repeated except that the polymer from
Example B10 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with TMPTGE (20% on the polymer) and the
spinning condition was 300 rpm for 3 sec followed by 1500 rpm for 20 sec.

Example C12a

[0102] The process of C1a was repeated except that the polymer from
Example B10 was dissolved in PGMEA (25 wt %) along with TrisP 3M6C-2-201
(25% on the polymer) and with TMPTGE (20% on the polymer) and the
spinning condition was 300 rpm for 3 sec followed by 930 rpm for 20 sec.

Example C13a

[0103] The process of C1a was repeated except that the polymer from
Example B13 was dissolved in PGMEA (25 wt %) along with Tris-P PAC (25%
on the polymer) and with TMPTGE (20% on the polymer) and the spinning
condition was 300 rpm for 3 sec followed by 1520 rpm for 20 sec.

Example C14a

[0104] The process of C1a was repeated except that the polymer from
Example B14 was dissolved in PGMEA (25 wt %) along with Tris-P PAC (25%
on the polymer) and with TMPTGE (20% on the polymer) and the spinning
condition was 300 rpm for 3 sec followed by 1980 rpm for 20 sec.

Example C15a

[0105] The process of C1a was repeated except that the polymer solution
from Example B15 along with Tris-P PAC (25% on the polymer) and with
VG3101L (20% on the polymer) and the spinning condition was 300 rpm for 3
sec followed by 830 rpm for 20 sec.

[0106] The dielectric constants of all of the films, other than the films
of Examples C9a and C12a, were uniformly low at all frequencies, ranging
from a low value of 2.9 to 3.1 at 1 MHz and from a low of 3.1 to 3.4 at 1
KHz. While the results for C9a and C12a were higher, they also exhibited
desirable low dielectric constant values ranging from 3.3 at 1 MHz to 3.7
at 1 KHz.

[0107] b: Transparency of Cured Film

[0108] The copolymer compositions as prepared for each of Examples C1a,
C3a, C4a, C6a and C13a-C15a were used to prepare films about 3 um thick
on glass plates. After a soft bake at 110° C. for 100 sec., each
film was exposed at 500 mJ/cm2 using a mask aligner having a broad band
Hg vapor light source (g, h and i bands). After exposure, the wafer was
post-exposure baked at 220° C. for 60 min under nitrogen
atmosphere to obtain a cured film. The glass plate coated with the film
was heated at 250° C. for 30 minutes in an oven under air, and the
transparency of the film at 400 nm wavelength was measured by using
ultraviolet-visible spectroscope (Hitachi U-2000). The resulting heat
treated films were labeled Examples C1b, C3b, C4b, C6b and C13b-C15b, and
the % transparency of each is provided below.

[0110] The copolymer compositions as prepared for each of Examples
C1a-C4a, C6a, C7a, and C12a-C15a were used to prepare and expose films
about 3 um thick on four inch thermal oxide coated silicon wafers. After
each film was cured, a portion of the film was removed from the wafer and
5% weight loss temperature was measured by TGDTA. The measurement
condition was 10c/min under N2 flow, The resulting weight loss
measurements were labeled Examples C1c-C4c, C6c, C7c, and C12c-C15c, and
are provided below. As seen, each of the films demonstrates a 5% weight
loss temperature in excess of 300° C. and can be considered
thermally stable at temperatures up to and including 300° C.

[0112] The copolymer compositions as prepared for each of Examples
C1a-C15a were used to prepare films about 3 um thick on glass plates,
After a soft bake at 110° C. for 100 sec., each film was exposed
at 500 mJ/cm2 through a chrome on glass mask using a mask aligner
having a broad band Hg vapor light source (g, h and i bands). After
exposure, each wafer was immersion developed using 0.4% TMAHaq for 10
sec, washed with &ionized water, then spun dry at 2000 rpm for 20 sec.
The final thickness of the polymer remaining of each wafer was measured
as was the resolution of 10 um lines and spaces. The results of these
evaluations, as well as the initial film thickness for each wafer,
labeled as Examples C1d-C15d, are provided below.

[0113] Referring now to FIGS. 4a and 4b, photomicrographs of portions of
images formed for Example C15d are shown. In FIG. 4a, 10 um lines and
spaces are seen to be cleanly resolved, while in FIG. 4b, 5 um lines and
spaces are also seen to be well resolved.

[0114] Thermal Flow Resistance

Example C5e

[0115] The heat resistance was measured by cutting the wafer patterned in
Example C5d into several pieces, heating the pieces to 220° C. for
60 minutes in an oven under N2, and then observing a SEM
cross-section of the heated piece. After 220° C. thermal cure,
pattern flow was observed.

Example C6e

[0116] The heat resistance was measured by cutting the wafer patterned in
Example C6d into several pieces, heating the pieces to 220° C. for
60 minutes in a N2 oven, then observing a SEM cross-section of each
heated piece. There is no pattern flow after thermal cure thus indicating
that the cured polymer film exhibits heat resistance and stability to at
least 220° C.

Example C7e

[0117] The heat resistance was measured by cutting the wafer patterned in
Example C7d into several pieces, heating the pieces to 220° C. for
60 minutes in a N2 oven, then observing a SEM cross-section of each
heated piece. There is no pattern flow after thermal cure thus indicating
that the cured polymer film exhibits heat resistance and stability to at
least 220° C.

Example C13e

[0118] The heat resistance was measured by cutting the wafer coated with
the film into several pieces, heating the pieces to 220° C. for 60
minutes in a N2 oven, then observing a SEM cross-section of each
heated piece. There is no pattern flow after thermal cure thus indicating
that the cured polymer film exhibits heat resistance and stability to at
least 220° C.

Example C14e

[0119] The heat resistance was measured by cutting the wafer coated with
the film into several pieces, heating the pieces to 220° C. for 60
minutes in a N2 oven, then observing a SEM cross-section of each
heated piece. There is no pattern flow after thermal cure thus indicating
that the cured polymer film exhibits heat resistance and stability to at
least 220° C.

[0120] g: NMP Tolerance

Example C6g

[0121] The formulation in Example C6a was spun onto 3 inch thermal oxide
silicon wafer at 300 rpm for 3 sec followed by 1300 rpm for 20 sec, soft
baked at 110 ° C. for 100 sec to give a polymer film of about 2.3
microns, then exposed at 500 mJ/cm2 using a mask aligner having a broad
band Hg vapor light source (g, h and i bands). After exposure, the wafer
was post-exposure baked at 220° C. for 60 min under nitrogen
atmosphere to obtain a cured film. The wafer was soaked into NMP at
40° C. for 10 min, and then measured film thickness. The film
thickness remained 2.3 um and peeling was not observed.

Example C15g

[0122] The formulation in Example C15a was spun onto 3 inch thermal oxide
silicon wafer at 300 rpm for 3 sec followed by 1300 rpm for 20 sec, soft
baked at 110° C. for 100 sec to give a polymer film of about 2.46
microns, then exposed at 500 mJ/cm2 using a mask aligner having a broad
band Hg vapor light source (g, h and i bands). After exposure, the wafer
was post-exposure baked at 220° C. for 60 min under nitrogen
atmosphere to obtain a cured film. The wafer w. s soaked into NMP at
23° C. for 60 min, and then measured film thickness. The film
thickness remained 2.56 um (4% gain) and neither crack nor peeling was
observed.

[0123] It will be understood that the data provided herein above
demonstrate that the copolymer embodiments in accordance with the present
invention, as well the composition embodiments that encompass such
copolymers are useful for forming self-imageable, thermally stable,
highly transparent low-K, dielectric layers. More specifically, such
copolymers and layers made therefrom are readily applied to a substrate
using well known microelectronic and/or optoelectronic processing, have
dielectric constants at or below 3.9 and exhibit thermal stability to
temperatures in excess of 300° C.

[0124] It will further be understood that while examples of methods for
making the copolymer embodiments in accordance with the present invention
have been provided, such methods are not limiting. That is to say that
other reaction times, temperatures, solvents and the like can be used to
adjust and control characteristics of the copolymers, copolymer
compositions and films, layers or structures made therefrom. For example,
where a polymerization example discloses the use of AIBN as a
polymerization initiator, other such initiators such as the exemplary
initiators listed herein above can also be employed and can provide
copolymers having different molecular weights than those disclosed in any
specific example. It will be understood that such a modification is
within the scope of the embodiments of the present invention. Similarly
other casting and polymerization solvents can be employed and where such
other solvents are used to make the copolymer, composition and film or
layer embodiments described herein, such other solvents are also within
the scope of the present invention.